I don’t know about kobo but with koreader you can use OPDS as a source. They also have a specific plugin for wireless calibre connection.

Note for koreader you can hook it up to kavita or audiobookshelf to download books wirelessly. I’m mainly annoyed by the manual calibre step. I have to do the same thing to remove drm, any idea if it can be automated?

I have kavita and audiobookshelf running as containers on my NAS. I don’t have a good automation for getting books there since I usually need to remove DRM, which is a bit manual with calibre. Kavita is then coupled to my ereader (tolino) running koreader.